In the case of four-wheel drive motor vehicles, it is particularly beneficial to be able to servocontrol the speed of an axle of the vehicle with respect to the speed of the other axle. The desired mismatch between the speed of the wheels of the front axle and the speed of the wheels of the rear axle may be different depending on the running conditions of the vehicle.
For example, high accelerations may occur, for low speeds, when a traction-based engined vehicle is started, to such an extent that it is possible to favor a low slippage between the front wheels and the rear wheels in order to increase motivity. Conversely, for high speeds, a more sizable mismatch between the front axle and the rear axle will be tolerated in order to favor stability.
A method which improves the slippage during phases of quasi-static running by modifying the control of torque distribution between the front axle and the rear axle is known from document U.S. Pat. No. 5,752,211. This modification is carried out by reintroducing signals into the actuator regulating system.
However, on account of the modification of the regulating loop, the stability of the vehicle is not guaranteed with this type of method.